SX-Key

Parallax SX is a discontinued line of microcontrollers that was marketed by Parallax, from a design by Ubicom. Designed to be architecturally similar to the PIC microcontrollers used in the original versions of the BASIC Stamp, SX microcontrollers replaced the PIC in several subsequent versions of that product.

The designs for the devices are owned by Ubicom (formerly Scenix, hence "SX"). The SX dies were manufactured by Ubicom, who sent them to Parallax for packaging. Ubicom had made processors with 18, 20, 28, 48 and 52 pins, but because Parallax did not have packages for 18 and 52 pins chips, the SX-18 and SX-52 were discontinued.

On July 31, 2009, Parallax announced that the SX line had reached its production EOL (End-of-Life) as Ubicom would no longer be manufacturing dies based on the designs; after the supplies from the final "lifetime buy" have been exhausted, the associated products cannot be restocked. In the same announcement, Parallax expressed that availability of its own products based on SX devices would not be impacted and that technical support would remain available.

The Parallax's SX series microcontrollers are 8-bit RISC microcontrollers (using a 12-bit instruction word) which have an unusually high speed, up to 75 MHz (75 MIPS), and a high degree of flexibility. They include up to 4096 12-bit words of Flash memory and up to 262 bytes of random-access memory (RAM), an eight bit counter and other support logic. They are especially geared toward the emulation of I/O hardware in software, which makes them very flexible. While Parallax's SX micros are limited in variety, their high speed and additional resources allow programmers to create 'virtual devices', including complete video controllers, as required. For example there are software library modules to emulate I2C and SPI interfaces, UARTs, frequency generators, measurement counters and PWM and sigma-delta A/D converters. Other interfaces are relatively easy to write, and existing modules can be modified to get new features.

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